Apparatus for trimming blanks



July 26, 1927.

R. M. HEAMES ET AL APPARATUS FOR TRIMMING ammxs Filed Sept. 20, 1923 9 20 a Z/ lgx I /a g li 5/! w0$ M /3 0 I -22 I" 5/" 6 /a I; I V 1 A 13 Patented July 26, 1927.

UNITED STATES PATENT OFFICE.

RICHARD M. HEAMES, OF GROSSE POINTE VILLAGE, AND BIRGER W. LINDQUIST, OF DETROIT. MICHIGAN.

APPARATUS FOR TRIMMING BLANKS.

Application f led September 20, 1923. Serial No. 683,183.

lhis invention relates in general to improvements in the art of finishing articles such as metallic bodies, and relates more specifically to an improved method of and apparatus for automatically trimming blanks or the like in rapid succession.

An object of the present invention is to provide an improved process of automati cally trimming blanks in rapid succession.

Another object of the invention is to provide simple and efiicient apparatus for com mercially exploiting the improved process of trimming blanks.

Prior to the present improvement it has been practically impossible to trim the heads of cap screw blanks or similar objects, with a single cutting operation to produce a resultant uniformly smooth iinished surface throughout the entire cut. In all commercial prior methods of finishing cap screw and similar blanks by a single operation. the completion of the cutresults in a tearing of the surplus stock from the blank thus producing relatively rough and unfinished final surfaces. In order to produce dressed blanks having uniformly smooth and attractive finished surfaces. a succession of trimming operations have heretofore been resorted to, the final or finishing out being taken subsequently to an initial or roughing cut lVhile such double trimming produces commercially satisfactory final product,- the method is relatively costly and materially impairs the capacity of the trimming plant exploiting the same. k

The present invention conten'iplates' provision of an improved method of trimming blanks in succession and of simple and durable apparatus for commercially exploiting the method, whereby final and highly satisfactory trimming of blanks is assured by a single cutting operation. lVith the in'iproved method and apparatus. the capacity of a trimming machine may be made at least equal to that of any prior rough trimmer, and the finished product is equivalent in quality to that obtained with the prior double trimming method. The present invention also contemplates provision of trimming tools the cutting edges of which are more eil'ective than those of prior tools of this character. and which are less subject to breakage and wear. 'lhese and other objects and advantages of the present inveir tion'will be apparent in the courseof the following description. 1 y

A clear conception of the several steps of the improved process and of the'details of construction and of the operation of apparatus embodying the present invention, may be had by referring to the drawing accompanying and forming a part of this specification in which like reference characters designate the same or similar parts'in the various views. 7

Fig. 1 is a part sectional view of an improv-ed cap screw blank ti'iiiii'i ii-rg machine showing the various elements thereof as they appear when no trimming is being effected.

Fig. 2 is a fragmentary enlarged sectional view of an improved trimming die and punch showing a cap screw blank in position preparatory to trimming.

Fig. 3 is a fragmentary enlarged sectional view of an improved trimming die and punch showing a cap screw blank in position immediately after the finishing out has been completed.

The improved trimming machine illustrated in the drawing comprises in general a stationary frame 3; a ram 11 reciprocable relatively to the frame 3; a trimmer die 5 removably supported within a bolster plate 4 secured to the frame 3; a pair of inner and outer movable punches 6, 7 respectively, carried by the reciprocable ram 11; suitable mechanism of well known construction for automatically positioning cap screw blanks 22 in succession between the trimming tools preparatory to finishing; and a pair of knockout elements or pins h. 12 cooper-at ing with the die 5 and punch 6 to discharge the finished blanks 22 from the machine. It will be obvious to those skilled in the art. that while-the present embodiment of the invention is applied to a machine in which the die is held stationary and the punch is moved, the principles of the present inven; tion are readily applicable to machines of the type in which the punch is stationary and the die is movable and to machines in which both the punch and die are mechanically movable durin trimming.

The trimmer die 0 is rigidly but removably supported by a stationary frame 3 and has a recess 9 of suitable form therein adjacent to the cutting edge of the die, this recess 9 preferably extending in close proxloo sleeve.

the threaded portion of the sleeve 14 and p imity to the cutting edge in order to provide an edge having .an acute cleavage angle. The outer punch 7 is movably. andad ustably supported by the reciprocable' punch holder 26 and has a recess 20 of suitable form therein closely adjacent to the nose or forward end of the inner punch 6. The recesses 9, 20 are preferably of similar formation and ordinarily follow the general shape of the cutting edge of the die 5. The hollow interior of the outer punch 7 provides'a compressed air chamber 23 which is communicable at suitable intervals with the recess 20 through a series of small holes 21, and with a main compressed air supply pipe 10 attached to the punch holder 26.

The rear extremity of the outer punch 7 coacts with an adjusting sleeve 14 which has screw thread coaction with the interior of thepunch holder 26 for purposes of adjustment, such adjustment of the sleeve 14 being possible by virtue of a hexagonal portion formed upon the exposed end of the A lock nut 15 which coacts with with an adjacent surface of vthe movable ram 11, serves the dual function of locking the sleeve 14 in adjusted position and. of

locking the punch holder 26 in position within the ram 11.

The inner chamber 23 o the outer punch 7 and. is normally bodily movable with the punch 7 and ram 11. The punch 6 is provided with a rear end flange 13 which is adapted to engage an abutment 24 formed upon the outer punch 7. When the flange 13 of the inner punch 6 is in actual contact with the abutment 24 of the outer punch 7, the forward extremity of the inner punch 6 protrudes slightly from the forward face of the outer punch 7 as shown in Fig. 3. The shape and size ofthe inner punch 6 is preferably such that the forward protruding end thereof will readily enter the central opening of the die 5 without strikingthe cutting edges. An internal sleeve 16 slidably fitting a central-bore of the adjusting sleeve 14, is urged forward against the rear end of the inner punch 6 by means of a relatively powerful leaf spring 17 or other suitable resilient resistance. The opposite ends of the spring 17 react against the ram 11 through adjusting jack screws 18 or other means for adjusting the tension of the spring 17 The knockout pin 8 is adapted to be automatically positioned within the central opening of the die 5 as shown in Fig. 1, and reacts against a shock absorber 2 the inertia of which is capable of decelerating the velocity of the finally trimmed blanks 22. The knockout rod 12 located within alined bores in the punch 6 and sleeve 16 and penetrating an opening through the spring 17 is coactunch 6 is located within the able with a stationary post 19 to move the rod 12 forwardly relatively to the punch 6 as the ram 11 is moved'rearwardly after a trimming operation has been completed. The movable ram 11 and the elements carried thereby, are periodically reciprocable in a manner well known to those skilled in the art, and which requires no detailed description herein.

During normal operation of the trimmer while exploiting the improved process and for the purpose of finishing cap screw blanks 22 with a single cutting operation, the ram 11 is being periodically reciprocated to simultaneously move the punches 6, 7 back and forth relatively to the stationary die 5. The successive rough cap screws 22 are automatically positioned between the die 5 and the punches 6, 7 while these elements are separated, with .the shank of the blank nearest to the punches and in alinement with the bore of the inner punch 6. The ram 11 is then moved forwardly causing the cap screw shank to enter the alined bore of the punch 6 is forced back into the outer punch 7 until its forward end is flush with the face of the outer punch 7 andits inner flanged end coacts directly with the forward extremity of the adjusting sleeve 14 as shown in Fig. 2. The cutting operation then proceeds against the force exerted by the spring 17, until the out has been almost completed. During such initial trimming, the chips 25 which are cut from the head of the blank 22, automatically enter the space provided by the recesses 9, 20 of the die and punch, and are positively confined closely adjacent to the trimmed surfaces. As the trimming operation proceeds, the untrimmed stock of the cap screw head eventually becomes insuflicient to resist the pressure exerted by the spring 17 and the inner punch 6 automatically becomes effective to rapidly impel the blank 22 forwardly to the positionshown in Fig. 3 thereby quickly completing the trimming operation. Due to the fact that the spring 17 is relatively powerful in action, the blanks 2 2 are frequently accelerated and acquire considerable velocity upon completion of the cut, but in such cases the shock absorber 2 automatically functions to When the trimming operation has been thus completed, the ram 11 and the elements carried thereby have their direction of movement automatically reversed, whereupon the knockout pin 8 and the rod 12 may become effective to remove the finished blank 22 from the die and punch 6 and to deliver the trimmed article from the machine. If the finished blank 22 has a tendency to remain within the die 5, the knockout pin 8 serves to thus discharge the same, while the knockout rod 12 by engagin the post 19 performs a like function if the b ank 22 remains within the punch 6 as the ram 11 recedes. When the. ram 11 and punch 6 move away from the die 5, air under pressure is automatically admitted through the pipe 10, chamber 23 and holes 21 and discharges the chips 25 from the recesses 20, 9, thus automatically preventing accumulation of chips near the cutting edges. By virtue of the fact that the ram 11 is ordinarily reciprocated at a-regular and relatively rapid rate of speed, it Wlll be apparent that the successive trimming operations and the removal of the finished blanks 22 and of the chips, are effected in rapid succession thus producing a machine having enormous capacity.

The final cut is smooth and clean throughout its entire extent and tearing of the surplus stock away from the body of the blank 22 during completion of the cut is positively eliminated by confinement of the chips 25 within the recesses 9, 20 and by the rapid forward movement of the blank during completion of the cut. Such result is attained with a single cutting operation and the finished product has been proven e uivalent, if not superior in quality to that o tainable with the prior relatively slow and cumbersome double trimming method. While the improved die and punches are slightly more expensive than prior elements of this character, when initial cost alone is considered, it has been found that these improved elements retain their cutting edges in effective condition for a relatively long period of time due to the provision of acute cleavage angles at the cutting edges by virtue of the recesses 9, 20. While the resilient resistance afforded by the spring 17 has been illustrated and described. as applied to one element of a compound punch, it will be obvious that such resistance may readily be applied to one element of a compound die or to the single element of a single die, without departing from the present invention.

It should be understood that it is not desired to limit the present invention to the exact succession of steps of the process or to the exact details of construction and operation of the apparatus specifically herein shown and described, for obvious modifications within the scope of the appended claims may. occur to persons skilled in the art.

It is claimed and desired to secure by Letters' Patent 1. In combination, a cutting element, means for simultaneously applying positive and resilient pressures acting in the same direction to ur e a blank against said element, and means or subsequently applying said resilient ressure to accelerate the movement of the b ank past the cutting edge of said clement.

2. In combination, a cutting element, means for applying a positive pressure to urge a blank against said element, and means for subsequently applying a resilient pressure acting in the same direction to further urge the blank against said element.

In combination, a cutting die, a ram for forcing a blank against said die under positive pressure, and a plunger for subsequently' forcing the blank against said die under resilient pressure acting in the same direction.

4. In combination, a cutting die, a ram for forcing a blank against said die under positive ressure to partially trim the blank, and a p unger carried .by said ram and formed to subsequently force the blank against said die under resilient pressure to finish the trimming operation.

5. In combination, a stationary cutting die, a reciprocable ram for forcing a blank against saiddie under positive pressure to partially trim the blank, and a spring pressed plunger carried by said ram for subsequently forcing the blank against said die under resilient pressure acting in'the same direction to further trim the blank,

In testimony whereof, the signatures of 1 the inventors are affixed hereto.

RICHARD M. HEAMES. BIRGER W. LINDQUIST. 

